1. Field of the Invention
The invention concerns a hand-held equipment for the examination of biological liquids such as whole blood, liquor, urine and serum with the aid of electrochemical biosensors without costly preceding analysis being carried out.
2. Description of the Related Art
For a fairly long time biosensors have been applied as sensitive and selective detection methods in analysis, in particular of medical diagnostics. For this purpose, respective biosensors are installed in analyzers which allow to carry out a fast inexpensive and notably proper examination of the respective parameters in central laboratories where many samples have to be examined. This requires, as a rule, a sample throughput of 80 180/h.
The analyzers are based on various principles. For the most part, they are operated with a continuous air segmented flow of the respective, highly diluted laboratory samples, i.e. this method requires the preparation of the solutions to be examined (e.g. whole blood) with a dilution of the analysis material being required. It is very costly to analyze individual samples by means of this equipment as the efficiency of analyzers becomes effective only in the case of a high number of samples being examined (ESAT.RTM. 6660 and ECA 180 from Prufgerate-Werk Medingen GmbH, EBIO (Eppendorf.RTM. from Eppendorf-Netheler-Hinz GmbH).
Furthermore, there are instructions known to measure individual samples also without preceding analysis being carried out which, however, are very immovable owing to a high integrated measuring comfort, thus being unsuited for a local application (YSI 2300 STAT of YSI Incorporated and STAT Profile PLUS of NOVA BIOPMEDICAL GmbH).
From EP-A-0 520 443 a portable sensor equipment is known which consists of a waste collector, liquid canals and intakes and an electrochemical sensor in a case and an external calibration unit.
For the time being, commercialized mobile systems with integrated biosensors are too expensive owing to the high measuring comfort (internal calibration), require too much maintenance and are operated with too long transport ways for the sample to be measured. For this reason, in addition to a comparatively high price, delays and pollution will result which have detrimental effects on the quality of analyzing.
All measuring systems applied locally to determine parameters such as glucose and lactate are at present based on nonreusable consumables (test strips, photometric; strip electrode, amperometric). Thus the analysis is determined by the price of the test strip and the test strip is not calibratable as it may be used just once.